Method for producing acetylene



April 5, 1949. o. SPRING 2,466,617

METHOD FOR PRODUCING ACETYLENE Filed June l5, 1944 2 Sheets-Sheet 1 INVENTOR @Z'o .Spr/1%.

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pnil 5, 1949. SPRING 2,466,617

METHOD PRODUCING vACETYLEIE Filed June 15,- 1944 2 Sheets-Sheet 2 PREHEATED GAS OR HYDROCARao/v AIR COI LS COMBUSTION SPACE OF PURA/ACE l 14 sreA MT ABOVE METALIN sur l L MQLTEN METAL DRAW cm;`

v BY W" Oi'o Sp1-agi A rrUR/YEY Patented Apr. 5, 1949 2,466,617 METHOD FOR PRODUCING ACETYI-JENE Application June 15, 1944, lSerial No. 540,385

11 Claims. i

This invention relates to an improved method and apparatus for producing acetylene from hydrocarbons.

It has been proposed heretofore to produce acety1ene from hydrocarbons, such as methane, by means of the electric arc, by direct thermal treatment of such hydrocarbons and by incomplete combustion of these hydrocarbons.

In comparison with the known methods of producing acetylene the present process has definite improvements. Its operating and construction costs are low, it is strictly continuous with long operating cycles of high efficiency and it is particularly adaptable to large scale operations.

One method of producing acetylene utilizing the process of partial combustion is described in U. S. Patent 1,940,209. However, the process described in such patent entails small scale operations. It has been found as a result of considerable experimentation that an attempt to -produce acetylene on any substantial commercial scale, according to the disclosure of the patent, is fraught with considerable difficulty particularly with respect to achieving good yields and to designing an effective apparatus which will withstand the high ytemperatures involved.

As a result of extended research it has been found that the salient feature in the ypyrolysis of hydrocarbons to acetylene is a complete or homogeneous and substantially instantaneous mixing of the hydrocarbons and air. If such a homogeneous mixin-g can be quickly effected the pyrolytic reaction is much more nearly quantitative `and particularly if the reaction is carried out in a reaction zone so designed as to avoid loss of heat of reaction. Upon quickly quenching the reaction products decomposition of the initially formed acetylene is inhibited and high yields yare secured.

Of still greater importance the provision of instantaneous homogeneous mixing enables the adaptation of this new method to large scale operatons.

As will be seen hereinafter, improved resultsy may be achieved when employing a novel design of conversion equipment and by utilizing special materials of construction in the furnace and reaction zones.

In order to enable a more ready comprehension of the invention there is shown in the accompanying drawings a typical illustrative embodiment of an apparatus for producing acetylene according to the invention in which:

Fig. 1 is a ow sheet of the process with the furnace structure in vertical section.

Fig. 2 is an enlarged vertical section of the reactor shown in Fig. 1.

Fig. 3 is an enlarged vertical section of the lower portion of the reactor.

Fig. fl is a plan view of the bottom of the gas inlet tube.

As will be seen from an inspection of the drawings the conversion unit comprises a suitable furnace l which includes a preheatng section 2 and a combustion chamber 3 to which heat is supplied from the burner 4. The two sections are established by the bridge Wall E which extends from the oor of the furnace upwardly a predetermined distance below the furnace roof.

As will be observed, within the furnace is mounted the continuous coil 6. This coil preferably is constructed of a suitable refractory material such as Carbofrax (silicon carbide). The coil is constructed of standard interchangeable `and readily replaceable units, namely, the tube sections l in-I terconnected at the lower and upper ends by the return bends 8. These tubes may be of any suitable standard size, as for example, 4 inch internal diameter and 52 inches long. The joint between ythe tubes and the return bends are eectively sealed with any suitable cement. It is to be observed that the tubes are supported wholly on the floor of the furnace by the lower return bends and the upper return bends are spaced an appreciable distance from the roof ofthe furnace. With this type of construction the entire weight `of the tubes is taken as Ia vertical compression load and the Itubes are free to expand and contract in a vertical direction with change in temperature in the furnace, that is to say, no extraneous stresses are imposed on the tubes during thermal expansion.

The tube coil ll is utilized for heating the air which is to be used for combustion of the hydrocarbons entering the reaction tube thereby providing the heat necessary to satisfy the negative heat of formation of acetylene. As shown, air is fed into the inlet end 9 of the coil and is discharged at any desired temperature to the upper portion of the reaction tube I0.

`f As shown, particularly in Fig. 2, the reaction chamber comprises an elongated tube which is preferably composed of the same material as the heating coil 6. With this type of construction, the difficulties of differential expansion of the air heating tubes and the reactor encountered 'in the case of ceramic air heating tubes and metallic reactor are obviated. The novel design of the reactor, as will be shown later, further assures freedom from differential stresses.

The tube I is of any suitable size, as for example, about 52 inches long with an internal diameter of 4 inches. As will be seen hereinafter, the enlarged reaction chamber dif'fers radically from the reaction chamber heretofore proposed. The latter comprised tubular or slot-shaped units of very restricted cross-section, i. e., of the order of from 2 mm. to 10 mm. The advantages of an enlarged reaction chamber over'one of such restricted cross-section are striking particularly in an operation in which a large volume thruput is practically a prerequisite to commercial operation.

The lower portion of the tube, as will be noted, is of special design by reason of which numerous advantages are secured. As will be seen, the lower portion of the tube essentially is a double wall construction. The inner wall is formed by the lower portion of the tube itself. The second outer spaced Wall- II is established by the` bellshaped Carbofrax section that is cast into the -tube at the section I2. The bell-shaped flange may be scored as at I3 so as to provide a joint or weakened section at which any break would preferentially occur. It is particularly to be observed that the lower end of the 'bell-shaped flange projects below the horizontal plane of the end of the tube. Thus, when the tube'is placed on a flat or plane surface it is wholly supported through the flange and the end of the tube itself is subjected to no supporting stresses.

As will be seen from an inspection of Fig. 2, the double Wall structure of the end of the tube is designed so as to provide an hermetic seal between the intensely hot reaction tube and thev cool quench box. This is accomplished by the association of the lower end of the tube with a liquid well structure I4 mounted on the top of the quench box. The furnace floor is cut away, as at I5, to provide a circular opening. The well structure includes the steel plate I6 whichrests upon and is secured to the furnace floor adjacent the aperture in the furnace floor. 'I'his'plate is provided -with the spaced cylindrical sections I1 and I8 which are.cast, welded or otherwise secured to the plate Ii. ,The external flange Il is tapped to receive af drawotf line I! controlled rby valve I9' through which molten metal may |be withdrawn prior to shutdown. As will be seen. the plate alsoserves as the top of the quench box and seals ofi the furnace from the box.

4 steam is bled into the space above the level ofthe liquid to form a blanket which inhibits oxidation of the metal. In the place of steam other inert gases such as flue gas or nitrogen may be used to Prevent the oxidation of the sealing metal.

As noted previously, the end of the tube I0 is spaced an appreciable distance above the plate Il' so that however much it expands it does not contact the plate and therefore is not placed under any stress. This is of particular importance for this end of the tube is subjected to the maximum temperature of this operation and at such temperature its tensile properties are poor. By supporting the tube through the medium of the outside flanges II a longer operative 'life of the tube is insured.

As described previously, the communicates directly with the reaction tube IU. 'Ihis connection, as shown, comprises the L 3| which is of the same material as the heating coil and theV reaction tube. These Joints are sealed with asuitable cement. 'Y Y The upperface of the L connection is cored to 'receive the'novel mixing unit 3l. This unit, as

shown, is 'connected with the line I2, through l Vwhich preheated liydrocarbonV gas is fed.

As intimated previously. the function and designof the mixing unit ll is of paramount importance in the process and constitutes one of the main features Vthat differentiates the present method from prior operations.

As has been explained, it had been thought b prior investigators in the field, an effective reaction ofthe type contemplated` could be achieved only in a reaction chambe of drastically restricted cross-section. But it Vhas now been l found that these drastic mechanical limitations need not at'all 'be imposed. As a result of extensive` experimentation and test it has been as- 40 certalned that the essential factor in effecting the reaction and insuring high yield is the assurance of a'homogeneous and instantaneous mixing of the hydrocarbon gas and heated air. This can be effectively accomplished 'by subdividing the gas stream into a plurality ofsmall streams as it enters the airfstream. The function of the When the reactor tube is assembled inthe fur` `isfactory results.

phere and, hence any desire pressure condltions within limits of the depth of themoltenmetal' may be maintained in the tube.v

It has ibeen found that after operation of unit if the molten `metal constituting the seal is allowed to solidify inconta'ct" with the bell flange,`

the

breakage of the latterioften occurs. This may f readily be avoided and-Ian ;increased life ofthe tube insured by withdrawing-the moltemmetalf through the line I9 at the time of shutdown.

,It has also been found that-under the temperatures of operation there is a tendency` ofthe metal of the liquid seal to oxidize. Thismay be unit 3i is therefore to effect this subdivision so that the preheated vhydrocarbon gas is dispersed through and intimately admlxed with the heated air to insure instantaneous mixing. It has been ascertained that when such instantaneous homogeneous mixing is achieved a reaction chamber of relatively substantial size may be utilized. For example, operations have been conducted, according to the invention, in which a reaction chamber 24 inches long and 1.5 inches internal diameter has been employed with eminently sat- Itwwas ascertained that the yields so obtained were at least as good as those .obtained with reactionslots of restricted crosssection. Furthermore, better results from an "rp'eratioristandpoint were experienced.

'I'hesubdivisionof the gas stream into a series of small cross-sectionfstreamlets at the point of contact with the air stream may be effected by a number of specifically different units. The

important factor in the design of the mixing unit l is Vthat the `apertures in they mixer shall be as Y :small asis practicable. In operations which have been conducted mixing units were employed having a plurality of orifices 'which' were V. inch in r.diameter or width. It has been ascertained that the wid-th of the orifice should not exceed subavoided by inserting tube 2l through the metal;

pool. This tube is connected to a steam line and stantlally%` inch. The size of the several orifices and their relative position should be such that air heating e011 l the length of time necessary for the air stream to travel to the center of the gas stream should not be more than approximately of the time the reaction gases remain or are retained in the reaction zone.

It will be appreciated then, that the design of the mixing element 3l may be widely varied. The orifices may be of any desired configuration within the dimensional limits expressed above. The orces, for example, may be simple, circular apertures, elongated slots and the like. The unit shown in Figs. 2 and 4 which has been employed very successfully, comprises a tubular member having the closed bottom portion of about 11/2 inches in diameter. This is formed with the peripheral slots 33 which are approximately 1/8 inch in width and about 1/2 inch or more long. The bottom portion is also formed with the intersecting transverse slots 34 of the same width as the curved peripheral slots 33. Obviously, as noted, the openings may be of any other desired shape. The bottom of the mixing unit 3| may also be in lche form of a hemisphere through which a plurality of circular holes of small diameter are bored. These holes or apertures may also be positioned in the vertical walls of the mixing unit close to the bottom.

As will be seeninFig. 2, the mixing unit 3l quench unit. The quench box may be of any desired shape and is shown herein as comprising the cylindrical wall of steel or other'suitable material. This may be provided with a separate or integral flange 43 which is bolted, welded or otherwise secured to the plate i6 so as to form a pressure-tight seal. i

The quench unit is provided with a pluralityof water lines 44 each with a spray head 45. AThe spray heads, as will be noted, are positioned along the axis of the eluent reaction gas stream and serve to quickly reduce the temperature of the gas to below the boiling `point of water. This water spray also serves to solidify, ageregateand carry down higher aromatics of the-type of anthracene. These being heavier than water collect at the bottom of the water seal, This deposit may be periodically removed and passed to container 54 through line 41 for recovery of the valuable hydrocarbons. l'

In a typical operation the quench box should be approximately ilve times the diameter of the reaction tube. The height of the water seal at the base of the quench tank, as will be understood, may be varied. In normal circumstances a vacuum of between about 1/2 and 1 inch of merprojects into the air stream as the latter enters the upper end of the reaction tube. At this point instantaneous and homogeneous mixing of the gas and air takes place.

Due to the fact that the mixing unit 3l' projects into the hot air stream which latter is at a temperature above the cracking temperature of the gas it is necessary to take special precautions to prevent cracking of the gas and consequent accumulation of carbon adjacent the surface of the mixer, since such carbon accumulation would soon clog the orifices. This carbon accumulation can be avoided by controlling the temperature of the entering gas stream to a point suciently low to preclude such cracking. This temperature will vary depending on the conditions of a particular operation, more especially on the temperature of the air stream. For example, in a typical operation where the air stream is at a temperature of 2250 F. it is necessary to carry the gas stream at a temperature of about 950 F. or below, to avoid carbon accumulation.

A long series of tests have established that when instantaneous and homogeneous mixing is insured at the point of contact of the gasand air streams a very high yield of acetylene is obtained when employing lower temperatures than heretofore required and but little carbon is produced. This latter feature is a particularly important feature since it minimizes or eliminates the necessity of periodically burning out the accumulated carbon as was required under prior practices thus commensurately increasing the operating eiciency of the apparatus. Furthermore, as will be appreciated, the reduction in carbon formation greatly simplies the subsequent steps of collecting and concentrating the acetylene-containing gas.

The reaction gases formed in the reaction zone are drastically quenched whereby their temperature is decreased to 212 F. or below. This is accomplished in the quench unit 4i! shown in Fig. 1. As there shown, the unit is comprised of the top plate I6, which serves as the support for the reaction tube I0, the side walls 4l and the open base 42. The base 42, in effect, is a container for the accumulation of liquid and seals the water seal base 50.

cury is maintained in the'quench tank. Under these circumstances the water within the cylinder 4D will rise to a.- height of approximately 1 ,foot above the level of the overow line and the water in box 42 may be several inches deep. The base of the quench tank is provided with the water overflow line 46 which discharges to the tank 5 4.

The cooled reaction gases are withdrawn from the quench tank through the line 48 which is positioned well above the water level therein. The gases are discharged from line 48 to a lower section of a cooling andscrubbing tower 49. This tower, like the quench box, is' provided with a The gases passing upwardly in the tower are contacted with a counter-current spray of water admitted tothe top of the tower through recycle line 5| and from water make-up line 52.

The water accumulating in the vbase of the tower continuously overflows through line 53 and passes to a settling tank or decanter 54. The settled sludge, containing solidified aromatic 'cofistituents,- may be periodically or continuously withdrawn` through line 55 to decanter 54 `from which it may `be withdrawn and treated inany desired manner to recover the valuablel constituents. Water from'the settling tank is picked up by pump 56 and recycled through line 5| tothe top of tower 49 to contact the incoming gas. Similarly, water from tank 54 is forced by pump 56 through line 44 to be sprayed into the quench box.

The cooled and partially scrubbed gas is with drawn from the upper part of tower 49 and is passed through the line 5l to the lower portion of the solvent scrubbing tower 58. In this tower the gases are contacted with a downwardly flowing stream of a solvent admitted through line 59. Make-up solvent may be admitted from a source of supply through line 6U. The solvent employed is one which has a selective amnity for certain of the more volatile aromatics, such as napthalene. The scrubbed gas passes out of the top of the tower through line 6| for further treatment to be described. The solvent accumulating in the base of the tower is continuously passed to the aromatic recovery stage 62 and the stripped solvent is recycled to the top of the tower through pump 63 and line 64. With many solvents which may be used in this tower an appreciable quantity of acetylene may be extracted. If it is desired to recover this quantity the overhead material distilled off from the solvent may be fractionated to separate the acetylene which may be returned to the system, as for example, to the intake side of blower i5.

The gases which are scrubbed in tower 58 pass overhead through line BI and are forced by blower 85 through the surge tank 66 to the compressor l1. This blower also functions to draw the air through the preheating tubes by operating at such a rate as to establish a slight vacuum on the quench box. 'The proportion of air enteringA the reaction tube is established by metering the total volume of reaction gases passing to blower 65 by means of an orifice meter B8 placed in line 6|. As will be appreciated, the gas entering the reaction tube is measured by means of an orice meter 58 placed in the gas line 32 before the preheater.

' derivatives of acetylene.

The scrubbed gas discharged from the top of the tower 10 passes through line 9| and pressure control valve 92 to any suitable treating unit 8l. This exit gas, as will be noted, has been freed of carbon and aromatics and consists of acetylene and some ethylene diluted with other gases, such as N2, CO, CO2, H2 and the like. In ordinary operations the gas contains 4% or more of acetylene. This may be further treated by any suitable method to produce more concentrated acetylene or it may be treated directly to produce For example, the acetylene-containing gas may be treated in unit 98 to hydrate the acetylene to acetaldehyde by contacting the dilute gas with a suitable catalyst such as mercuric sulphate in sulfuric acid.

\ As an alternate method this gas issuing from By means of the compressor the gas is compressed to any desired degreeand the compressed gas is fed continuously to a lower section of the solvent scrubbing tower 10. Gases passing upwardly through the tower 10 are scrubbed with a limited quantity of a selective solvent which has a selective ailinity for the contained aromatica and other substances boiling higherthan acetylene. This solvent, which may be a gas oil is fed to the topA of the tower through line 1|.

It will be appreciated that when employing a solvent, as the scrubbing medium in tower 10,.

not an inconsiderable amount of acetylene will acetylene. Thestrlpped solvent accumulating in a the base of the tower passes through the line 15, through preheater 12, wherein it is utilized to preheat the extract passing to the bubble tower, and thence through line 16 and surge tank 11.

From the surge tank the stripped solvent is picked up by pump 18 and recycled to the top of the tower. Makeup solvent may be introduced into the cycle at any desired point, asfor example, through line 19.

The material distilled off from the solvent in tower 1l is passed through the cooler 80 and thence to the separator 8|. A condensate consisting essentially of benzol is withdrawn from the bottom of the separator through line 82. The uncondensed fraction containing acetylene and other gases is passed overhead through line 83 to the compressor 8l. The compressed gas is then passed through line `85 to the condenser 88 and separator 81. In separator 81 any residual benzol is withdrawn as a condensate through line I8 and is passed, together with the fraction from separator 8| to storage. from separator 81 is passed through line 90 to the intake side of compressor 65 and returned to the' system, or under conditions where gaseous impurities therein would harm subsequent reactions or products, the overhead product is passed to operations where such impurities are harmless through line 84. Valves 95 and 96 may be operated to permit such alternate tlow.

The overhead fraction tower 10 may be passed through a solvent extractor in which a suillcient amount of a suitable Asolvent is used to extract substantially all of the stack, by constructing furnace with a double wall and causing the air to traverse the space between the walls or by means of an auxiliary furnace. Furthermore, if desired, a blower may be disposed in line 9 acting as a source of positive pressure on the air being introduced into the system, so as to give assurance that the required quantity of air is introduced without increasing the vacuum on the quench box above the desired level.

In some circumstances it may be desirable to protect the lower portion of the reactor I0 from the direct heat of the furnace. This may be accomplished by providing a layer of insulation of, for instance, high temperature brick.

` While the reaction tube I0 is shown as disposed within the furnace 2, thereby preventing heat losses from Within the tube, it is perfectly permissible to dispose the reaction tube in a separate furnace. This variation is effective under circumstances where it is desired to control the Atemperature obtaining within the reactor at a level substantially different from the temperature in the main furnace.

The'furnace may be constructed without the bridge 5 with the result that better advantages of radiant heat from the flame from burner 4 would be obtained although in such case the base of the reaction tube would not be as well protected.

The improved results accruing from the use of the described method and apparatus can more readily be appreciated from a consideration of typical operations carried out in .the described apparatus. In one operation propane was utilized as the hydrocarbon gas change. The gas was preheated to 950 F., was fed at the rate of 308 cu. ft. per hour together with air preheated to 2200 F. Upon analysis it was found that the yield of acetylene was 35% by volume of the feed gas. f

In another operation a preheated gas having a gravity of .77, comprised essentially of methane andethane was fed to the reactor at the rate o! 9 458 cu. ft. per hour together with preheated air at the rate of 1153 cu. ft. per hour. Analysis of the cooled eiiiuent gas showed a yield of 17.3% of acetylene by volume of the feed gas.

In another operation a preheated gas of .643 gravity was fed to the reaction chamber at the rate of 508 cu. ft. per hour and was intimately mixed with preheated air fed at the rate of 1108 cu. ft. per hour. The furnace temperature was 2250 F. Analysis of the cooled effluent gas disclosed a yield of 13.5% of acetylene by volume of the feed gas.

In another typical operation preheated gas of .750 gravity was fed to the furnace at the rate of 470 cu. ft. per hour and was homogeneously mixed with preheated air fed at therate of 1150 cu. ft. per hour. In this operation the furnace temperature was 2250" F. Analysis of the cooled exit gases showed a yield of 16.9% of acetylene by volume of the feed gas.

In yet another run preheated gas of .734 gravity was fed through the mixer to the furnace at the rate of 475 cu. ft. per hour and was intimately admixed with'preheated air fed in at the rate of 1150 cu. ft. per hour. The furnace temperature was 2400 F. Analysis of the cooled gaseous eiliuent disclosed a yield of 17.4% acetylene by volume of the feed gas.

It will be observed that the described process embodies many novel features which are specically and respectively correlated to insure im, proved results. The apparatus shown is designed so as to insure the optimum reaction conditions which conduce to satisfactory commercial yields. The unit described insures the desirably high 'degree of preheat of the air which is best attained by employed refractory tubes as the preheating structure. This high degree of heat insures a rapid combustion of that portion of the hydrocarbon charge which is necessary to attain the temperature required for the ultimate reaction leading to the formation of acetylene. As explained, theA provision of the novel mixing unit insures the diiiicultly attainable homogeneous and instantaneous mixing of the gas and air streams thus assuring high yields with thruputs large enough for profitable commercial operation. The expedient of positioning the reaction chamber directly within the furnace further facilitates to desired reactions in that heat loss from the zone of reaction by radiation from the exterior of the reaction chamber is positively precluded.' The mounting of the reaction tube within the furnace in turn is made possible only be establishing an eiiective pressure seal between the quench box and the interior of the furnace such as is eiectively done by the novel liquid seal described.

It is to be observed also that the structure. of the quench unit, although eminently simple, insures unobvious results. As has been explained, the use of a water spray permits a drastic reduction in temperature of the gases while using the cheapest coolant, namely, a recirculating stream of water. The use of an open base or pan at the bottom of the quench unit also contributes materially to the overall efficiency of the process. With this type of structure, i. e., using an open Water seal the lsolid. material which appears as such during quenching is allowed to accumulate in a unit from which it may, if desired, be readily removed. Again, the use of the open liquid seal as the pressure retention medium at the base of the tower serves, in a sense, as an effective buffer to take up or compensate for quench variations i0 or changes ln the degree of negative pressure in the tank.

As will be appreciated, these several novel features of operation and structure are each intimately correlated` and conduce to a simplied effective operation.

While a preferred embodiment of the invention has been described it is to be understood that this is -given didactically to illustrate the underlying principles of the invention and not as limiting the useful scope of the invention to the particular illustrative embodiment.

I claim:

1. A process of producing acetylene which comprises, passing a stream of preheated air to a reaction zone of relatively enlarged cross-section, concurrently passing .a stream of hydrocarbons to the reaction zone and homogeneously and in- -of smallycross-section at the point of contact with the entire heated air stream the said air stream being preheated to a temperature suf' iiciently high that upon admixture with the said hydrocarbons, the temperature of the resulting mixture is instantaneously raised to the reaction temperature, which favors the formation of acetylene and recovering the formed acetylene. 2. A process of producing acetylene which comprises, passing a stream of preheated air to a reaction Zone of relatively enlarged cross-section, simultaneously passing a stream of hydrocarbon gas which has been preheated to a lower temperature than the air to the reaction rone for impingement on the said air stream and `homogeneously and instantaneously mixing the air and gas by subdividing the gas stream into a series of small streamlets of small cross-section and introducing such streamlets into the entire heated air stream at the zone of impingement, the said air stream being preheated to a temperature suficiently high that upon admixture with the said hydrocarbons, the temperature of the resulting mixture is instantaneously raised to the reaction temperature, which favors the formation of acetylene and recovering the formed acetylene.

3. A process of producing acetylene which comprises, passing a stream of preheated air to one end of a reaction zone of relatively enlarged crosssection, simultaneously passing a stream of hydrocarbon gas which has been preheated to a lower temperature than the air to the reaction zone for impingement on the said air stream and homogeneously and instantaneously mixing the air and gas by subdividing the gas stream into a series of small streamlets and introducing such streamlets into the heated air streamv at the zone of impingement., the said air stream being preheated to a temperature suiilciently high that upon admixture with the said hydrocarbons, the temperature of the resulting mixture is instantaneously raised to the reaction temperature maintaining the gaseous mixture for a definitely limited period of time at such a temperature which favors theformation of acetylene, quenching the reaction gases to a temperature at which the formed acetylene is stable.

4. A process of producing acetylene which comprises, passing a stream of preheated air to a reaction zone of relatively enlarged cross-section, simultaneously passing a stream of hydrocarbons which has been preheated to a lower temperature than the air to the reaction zone for impingement on the said air stream and homogeneously and 5. A process of producing acetylene which comprises, passing a stream of air through a refractory ceramic coil and heating the air to a temperatureoi the order of 2000? F., discharging the heated airY into a reaction zone of relativelyy enlarged kcross-section, passing a stream of hydrocarbons, heated to a lower-temperature, to the reaction sone, subdividing the said hydrocarbon stream into a plurality ofstreamlets and discharging said streamlets into the entire stream of heated air. maintaining the gas mixture in the reaction loneat a temperature which4 favors the formation of acetylene, for a period of less than .1 sec., removing the reaction gases from the reaction sone and quickly cooling the reaction gases to a temperature at which the formed acetylene is stable. l

6. A process of producing acetylene which comprises, passing a stream of air through a refractory ceramic coil mounted in a furnace and heating it therein to atemperature of the order of 1700' F. and above, discharging the heated air into va reaction tube of refractory ceramic material, said tube being of 'relatively enlarged crosssection, whichftube is mounted within the furnace, passing a stream of hydrocarbons, heated to a temperature of the order' of 950 F., into the reaction tube, subdivlding'the hydrocarbon stream into a plurality of small streamlets and discharging such streamlets into the entire vheated air stream, maintaining the gas mixture in the reaction tube at a temperature which favors the formation of acetylene and for a period of less than .1 sec., then withdrawing and quenching the acetylene-containing reaction gases.

7. A process of producing acetylene which comgrises, passing a stream of preheated air to one md of a reaction zone of relativelyV enlarged cross-section, simultaneously passing a stream of heated hydrocarbon gas which has been preheated to a lower temperature than the air to the reaction zone for impingement on the air stream, homogeneously and instantaneously mixing the air and gas by subdividing the gas stream into a series of small streamletsfand introducing such streamlets into the heated air stream at the :one of impingement, the said air stream being preheated to a temperature sufciently high that 12 section simultaneously passing a stream of heated hydrocarbon gas which has been preheated to a lower temperature than the air to the same end of the reaction zone, subdivldin'g the gas stream into a series of individual streamlets inch or less in diameter or width at the point of contact with the entire air stream the said air stream being preheated to a temperature sufllciently high that upon admixture with the said hydrocarbons,

the temperature of the resulting mixture is instantaneously raised to the reaction temperature.

f maintaining the gas mixture for a definitely limitedperiod of time in the reaction zone at such temperature which favors the formation of acetylene and removing and cooling the acetylene-containing reaction product.

9. A process in accordance with claim 8 in which the cooled gas is scrubbed with solvents which selectively remove the aromatic constituents.

10. A process of producing acetylene which comprises, vpassing a preheated stream of air to one end of a reaction tube of relatively enlarged cross-section simultaneously passing a heated stream of a hydrocarbon gas which has been preheated to a lower temperature than the air to the said end of the reaction tube controlling the rate of ilow of said stream such that the ultimate mixture contains a preponderant amount of air, subdividing the gas stream into a plurality of small streamlets of inch or less in diameter or width, and discharging the streamlets into the entire heated air stream to insure homogeneous and substantially instantaneous mixing by fine dispersion of the lower temperature gas into higher temperature air, thesaid air stream being preheated to a temperature sumciently high that upon admixture with the said hydrocarbons, the temperature of thelresulting ,mixture is instantaneously raised to the reaction temperature passing the mixture rapidly through the reaction tube while maintaining the gas mixture at a temperature which favors the formation of acetylene,

. withdrawing and quenching the'reaction gases to upon admixture with the said hydrocarbons, the

temperature of the resulting mixture is instantaneously raised to the reaction temperature subjecting the resulting homogeneous mixture for a period of less than .1 sec.to a temperature which favors the formation of acetylene, cooling a temperature at which the acetylene is stable.

11. A process in accordance with claim 10 in REFERENCES crrnn The following references are of record in the le of this patent:

UNITED STATES PATENTS 4Number Name DateV 1,560,805 Schauman Nov. 10, 1925 1,579,240 Owen Apr. 6, 1926 1,823,503 Mittasch et al Sept. 15. 1931 2,030,070 Morrell Feb. 11, 1936 2,037,056 Wulff Apr. 14. 1936 2,047,545 Butteld July 14, 1936 2,079,017 Iddings et al. May 4, 1937 2,158,582 Isham et al May 16, 1939 2,179,378 Metzger Nov. 7, 1939 2,179,379 Metzger Nov. 7, 1939 2,318,688 Hasche et al. May 11, 1943 2,319,679 Hasche et al May 18, 1943 2,343,866 Hincke Mar. 14, 1944 2,377,245 Krejci May 25, 1945 FOREIGN PATENTS Number Country Date 290,322 Great Britain May 10, 1928 

